Computing devices using microprocessors are increasingly subject to power constraints as the speed and performance of the microprocessors increases. There is an increased desire for increased performance per Watt. With high-speed microprocessors that operate in the Gigahertz range at lower than 1 V operating voltage with operating currents peaking into the hundreds of Amps, power constraints are generally considered essential.
Integrated circuits are generally powered from one or more direct current (DC) supply voltages provided from either batteries, a converted alternating current (AC) source, or some combination. The power is provided through pins, leads, bumps, or lands on the integrated circuit package. Traditionally, power to high-speed microprocessors is provided by high-efficiency, programmable DC-to-DC (switch-mode) power converters located near the integrated circuit package that embodies the microprocessor.
Such a power converter is referred to as a buck converter. Buck converters generally require a number of components that are size-wise rather large as compared to the integrated circuit to which they provide power. The power converters generally include pulsewidth modulators (PWMs), one or more power transistors (e.g., power field effect transistors (FETs)), filter and decoupling capacitors, and one or more large inductors and/or transformers. Power converters may include one or more phases to supply the full output current.
The output of the power supply can be adjusted for specific needs of the microprocessor, such as specific voltage or current needs. Traditionally, information necessary to account for the specific needs of the microprocessor is either not available to the power supply/voltage regulator, or the accessibility requires signal lines for each of the separate items of information.